A case of yellow fever, an acute and contagious mosquito-borne viral disease, has been reported in a man in the Netherlands who recently travelled to Gambia and Senegal, the World Health Organization said on Tuesday.

The risk of further spread of the disease in the Netherlands is very low, the WHO said, in part because the virus is carried by types of mosquito rarely seen in northern Europe.

There have been no other reports of confirmed yellow fever cases from Senegal, Gambia or the Netherlands at this time, it added, but international health authorities have alerted officials in the two West African countries, since transmission and further cases there are more likely.

Yellow fever virus has the potential to spread rapidly and cause a serious public health impact in areas where people are not immunised. The WHO advises travellers to countries where the disease is common to get vaccinated at least 10 days beforehand.

The man in the Dutch case was not vaccinated. After returning to the Netherlands on Nov. 17 he felt ill and was hospitalised on Nov. 19 with symptoms of acute liver failure. He was still in hospital as of Dec. 10.

‘This case ... illustrates the importance of maintaining awareness of the need for yellow fever vaccination, especially in areas with favourable environments for yellow fever transmission, such as Gambia and Senegal,’ the WHO said.